Involuntary leakage of urine is a very common disorder. Urinary incontinence is not life threatening but it has a strong negative influence on Quality of Life.
About 10% of the population, mostly children and elderly people, have an insufficient control of their urinary bladder. The great majority of these have a minor degree of incontinence allowing them to lead a good life with the aid of simple measures such as a small incontinence pad or frequent change of underwear. The rest, about 1-% of the population, have a more severe incontinence that poses a serious social problem. Young people who are physically impaired regard the incontinence as a more severe handicap than the inability to walk. The urinary incontinence is considered to be the most serious obstacle for the creation of lasting relationship to other people, for their ability to live an independent, life, and for their adaptation to the society both on the private and the professional level.
Congenital malformations of the bladder or the nerves to the bladder (e.g. myelomeningocele) or traffic accidents with injury, to the spinal cord, or pelvic floor damage at childbirth, or infections of the nervous system (such as encephalitis or meningitis) cause the more serious forms of urinary incontinence. Furthermore, several of the diseases of old age, such as prostate hyperplasia of Parkinson's disease, may cause urinary, incontinence.
Generally, urinary incontinence is caused either by involuntary contractions of the bladder muscle (so called unstable bladder), or by insufficient contraction of the urethra sphincter muscle. Unstable bladder can be treated with medication or bladder training with good results. The situation is more problematic when the incontinence is due to a weak or damaged sphincter muscle. So far, there is no medication available that can increase the contraction of the sphincter without giving at the same time unacceptable side effects. The only efficient treatment today for severe cases is operation whereby an artificial sphincter is implanted around the bladder neck or urethra, controlled by the patient via an implanted pump system. This is major surgery, the cost is high (in, Sweden at least ,SK 100 000), the operation is unsuccessful in 15–25% of patients, and the device has a limited life span, meaning that reoperations will have to be performed in order to exchange components that have broken down. Therefore, many patients choose to keep their severe incontinence instead of going through a major operation with uncertain prospects.
Less than 1/1000 of the population have urinary incontinence due to a faulty sphincter muscle, the most severe and therapy-resistant form of incontinence. Still, this kind of incontinence is found in millions of patients on a global scale.
Since many years, the medical profession has been searching for alternative ways to treat patients with an incompetent sphincter muscle. Some centre (Munchen, San Francisco) tries esoteric and costly methods, such as transplantation of muscle or implantation of electrostimulators. Plugs or valves have been developed (e.g., U.S. Pat. Nos. 4,679,546 and 4,643,169) for implantation in the urethra, but previously used methods and materials have caused urinary stone and infection, so these devices have been abandoned. However, the development of biocompatible materials during recent years has improved the chances for prolonged survival of an artificial valve within the urinary tract.
SE-C-504 276 relates to a valve to be inserted into the urethra, which valve comprises a valve body formed by a permanent magnet, a stop and radially extending drainage holes placed in the middle of a surrounding valve housing, whereby the valve housing is present in a fastening means consisting of an expandable material, which, is expandable by means of a liquid introduced into said expandable material.
WO 00/33766 discloses a valve for bladder control comprising an elongate housing having a proximal end and a distal end and a lumen extending therethrough, a spring actuated valve stopper, and a valve seat onto which the stopper acts to prevent flow through the valve.
U.S. Pat. No. 3,812,841 relates to a urethra magnetic valve structure, which is held in the urethra by means of inflatable retention collars.
EP-A-0 53S 778 relates to a urinary incontinence valve disposable in the urethra of a patient for controlling the flow of urine therethrough, which valve consists of a tubular body having a proximal end, a distal end and an outer diameter small enough, to be able to place the valve in the urethra. The valve comprises a lumen extending from the proximal to the distal ends. Further the vale comprises a valve seating said lumen and a valve member acting upon said valve seat to close and open said valve by means of an actuator rod. The proximal and distal ends have diameters larger than the remaining part of the valve body. The actuating rod is moreover arranged to be placed within the urine bladder and be actuated upon by a abdominal pressure. This urinary valve does not provide options for being enlarged in place in the urethra but has to be brought in place with its full diameter, which is painful and may cause damages on the urethra mucous membrane causing infections which may easily enter the urine bladder.
WO 00/15140 relates to a urinary incontinence valve comprising a proximal end and a distal end and which is adapted to fit into the neck of a bladder or the upper part of the urethra, preferably not extending to any substantial part into the urethra. The proximal end may be conical to plug the bladder neck. The plug member is made of a resilient material, such as a polymer. A valve is situated in the plug member lumen. The valve as such may use shape memory alloys for opening/closing action, a hydrogel such as a polyelectrolytic gel.
U.S. Pat. No. 4,679,546 relates to an implantable shut-off device for regulating urination and consists of a titanium made conical collar provided with a cylindrical plug member into which a flow regulating valve is inserted. The collar is arranged to be placed at the urethra opening within the urine bladder and to lock the valve from being displaced from the bladder through the urethra. The implantation of such a rigid structure cannot be made through urethra but has to be made during a major surgery. The structure does not provide for a tight fitting of the valve receiving cylindrical part in the urethra but the valve structure may even get loose and enter the bladder as such causing a lot of discomfort: and inconvenience.